1. Field of the Invention
The present invention relates to a printer with a cutter capable of appropriately cutting a recording sheet pulled out from a paper roll after performing printing on the recording sheet.
2. Description of the Related Art
Nowadays, a great number of various types of thermal printers, which perform printing by pressing a heated thermal head against a special recording sheet that changes color when heat is applied thereto, are provided. In particular, use is suitably made in printing of various labels, receipts, tickets, and the like because smooth character printing and colorful graphic printing are possible without using toner, ink, and the like.
As the thermal printers, printers provided with a cutter mechanism for cutting the printed recording sheet are typically known (see Patent Documents JP 2007-38367 A and JP 11-123692 A). The cutter mechanism is normally set (auto cutter) to automatically cut the recording sheet when printing is terminated, and hence can be immediately used for a receipt, a ticket, and the like, as mentioned above.
Now, an example of the thermal printer is briefly described with reference to the drawings.
As illustrated in FIG. 15, a thermal printer 100 mainly includes a print unit 101, a fixed blade unit 102, and a movable blade unit 103.
The print unit 101 includes a platen roller 110 for feeding a recording sheet P pulled out from a paper roll R housed within a housing section (not shown), and a thermal head 111 provided to be opposed to the platen roller 110, which prints various information on the recording sheet P. The platen roller 110 is rotatably supported by a holder 112, and is rotationally driven by a motor (not shown). The thermal head 111 is pushed against an outer peripheral surface of the platen roller 110, and performs printing while interposing the recording sheet P with the platen roller 110.
The fixed blade unit 102 includes a fixed blade 116 rockable through a hinge portion 115, and a biasing portion 117 such as a coil spring, for biasing the fixed blade 116 in a push-up direction, and is arranged parallel to the print unit 101. The movable blade unit 103 includes a movable blade 120 and a slide portion 121 for sliding the movable blade 120, and is arranged to be opposed to the fixed blade unit 102 through the recording sheet P.
As illustrated in FIG. 16, any one of or both of the fixed blade 116 and the movable blade 120 is/are formed to be warped over a longitudinal direction (direction indicated by an arrow L). When the movable blade 120 is slid to be on an upper surface of the fixed blade 116, the fixed blade and the movable blade are brought not into surface contact but into point contact with each other. As a result, the recording sheet P can be smoothly cut with good sharpness.
An operation of the thermal printer 100 configured as described above is described.
First, as illustrated in FIG. 17, the platen roller 110 is rotated to feed the recording sheet P between the fixed blade 116 and the movable blade 120. At the same time, the thermal head 111 is operated to start printing on the recording sheet P. As a result, various information can be continuously printed on the recording sheet P. Next, upon termination of the printing, the platen roller 110 continues feeding the recording sheet P until a printed portion is beyond the movable blade 120. Then, when the printed portion is beyond the movable blade 120, the slide portion 121 slides the movable blade 120. As a result, the recording sheet P can be cut with the movable blade 120 and the fixed blade 116. At this time, the fixed blade 116 is pushed up by the biasing portion 117. Therefore, even when the movable blade 120 is slid to be on the upper surface of the fixed blade, no gap is generated between the fixed blade 116 and the movable blade 120. Thus, the recording sheet P can be smoothly cut.
However, the following problems still remain for the conventional thermal printer 100.
Specifically, in the conventional thermal printer 100, the fixed blade unit 102 and the movable blade unit 103 which function as a cutter are mounted to the print unit 101. Therefore, because the thermal printer is constituted by the combination of a plurality of units, there is no easy way to compactly configure the thermal printer. Accordingly, it is difficult to meet the need for a reduction in size.
Moreover, as illustrated in FIG. 17, a distance H between the center of the platen roller 110 and a cutting position with the fixed blade 116 and the movable blade 120 becomes inevitably large. Correspondingly, as illustrated in FIG. 18, the distance H from an end of the recording sheet P to the printed portion becomes large. Specifically, a cut piece of the recording sheet P has a large unprinted area (blank area). Therefore, the recording sheet P is needlessly long to be hard to handle as a ticket, a receipt, or the like. At the same time, the consumption of paper is accelerated to prevent the paper roll R from being efficiently used.
Further, the platen roller 110 is rotatably supported by the holder 112. During printing, the recording sheet P for some reason frequently enters into the gap between the holder 112 and the platen roller 110 (paper jam). In this case, as illustrated in FIG. 19, the recording sheet P entering into the gap is likely to be folded into several layers. Therefore, for a recovery operation of the recording sheet P, the printing is forced to be stopped. In particular, because the recording sheet P is folded into several layers, the recording sheet P cannot be easily removed. As a result, the recovery operation takes a long time. Moreover, even if the recording sheet P is successfully pulled out, the recording sheet is usually folded into an accordion shape. Therefore, the recording sheet cannot be reused and is wasted.